Evaporator unit



@y w, i4. c. .JOHNSON ,46, maremma mm Filed June 15, 1946 2 sheets-sheet1 vyjanr @ffm/imo Jann/30N Patented May l0, 1949 EVAPORATOR UNIT BernardC. Johnson, Mundelein, lll., assignor to I Houdaille-llershcyCorporation, Detroit, Mich., a corporation of Michigan Application June15, 1946, Serial No. 676,939

8 Claims.

This invention relates to heat exchangers having ducts so arranged as toefficiently distribute fluid for heat exchange relation with thesurrounding zones. Specically the invention relates to an evaporatorunit construction wherein diagonal ducts are used in intersectingrelation to provide 'a grid-like arrangement which will handlerelatively large volumes of refrigerant and avoid the necessity forheretofore used header ducts of relatively large cross sectional area.Thel invention also includes an arrangement of ducts in an L-shapedplate to provide a refrigerated shelf for the evaporator unit as well asa refrigerated back wall for the unit which will absorb residual coolingcapacity of refrigerant leaving the unit to dry the refrigerant andprevent frosting of the exhaust tube.

The evaporator units of this invention are preferably formed fromembossed secured together contiguous metal sheets bent in the shape of aU to define the bottom and side walls of a sharp freezing chamber. Theouter sheet is embossed to provide an inlet manifold duct longitudinallyalong the bottom wall. Distributing or feeding ducts extend at spacedintervals laterally from the manifold duct and thence upwardly into thelower ends of the side `wallsof the unit. The upper ends of the sidewalls of the unit each have two superimposed longitudinally extendingoutlet manifold ducts connected at their front ends. The lower outletduct of each pair has depending spaced collecting ducts aligned with theupstanding portions of the distributing ducts. Criss-crossed diagonalducts connect the upper ends of the distributing ducts with the lowerends of the collecting ducts. These diagonal distributing ductsintersect each other to provide a grid-like duct system accommodatinglarge volumes of refrigerant in good heat exchange absorbingrelationship with the surrounding zone.

The ducts, because of the large volume capacity afforded by theintersecting grid-defining arrangement need not have largecross-sectional areas to accommodate large volumes of refrigerant andshallow embossments on the outer sheet only are sufcient to define theseducts. As a result, the sharp freezing chamber is free from anyprotuberances to have increased storage capacity and the outer surfacesof the unit vare 2 free from large protuberances to accommodate mounting-of the unit close to the Walls of a refrigerator cabinet if desired.

The U-shaped unit has an L-shaped wall member composed of embossedsecured-together contiguous metal sheets mounted therein to provide ahorizontal shelf and a back Wall. Refrigerant is supplied through ductsin the horizontal shelf portion to a transfer tube at the rear end ofthe unit which supplies the inlet manifold duct in the bottom of theunit. The top outlet manifold ducts in the vtops of the side walls ofthe unit discharge through tubes at the back of the unit into ductsprovided in the back wall portion of the L-shaped member. These ductsare arranged with sumps so that any remaining heat absorbing capacity ofthe spent refrigerant is utilized to cool the back wall of the unitbefore the refrigerant is returned to the compressor and condenser ofthe refrigerating system. In this manner the back Wall acts as arefrigerant drying device to prevent frosting of the refrigerant returntube and to increase the elciency of the unit by causing it to utilizeall of the heat absorbing capacity of the'refrigerant.

It is then an object of this invention to provide a sheet metal typeheat exchanger free from chambers of large cross sectional areas andhaving an efficient duct system which places substantially all of theheat exchange liquid flowing through the unit'in good heat exchangerelationship with the walls of the unit.

Another object of this invention is to provide an embossed sheet metalrefrigerant evaporator unit free from heretofore used large diameterheader ducts and having a duct distributing sys.

tem which effectively places all of the refrigerant flowing through theunit in extended surface contact with the duct walls to increase theheat absorbing capacity of the refrigerant.

Another object of this invention is to provide a U-shaped sheet metalevaporator'unit for mechanical refrigerators wherein the side walls ofthe unit are embossed to have an arrangement of inteisecting diagonallyextending shallow ducts defining refrigerant' spreading conduits ofvenhanced capacity.

Another object of the invention is to provide a. heat exchanger with aseries of intersecting ducts presenting a grid-like appearance andeffective to distribute heat exchange uuid in emcient heat exchangerelation with the walls of the unit.

A still further object of the invention is to provide a sheet metal heatexchanger adapted for use as an evaporator unit in a mechanicalrefrigerator having an L-shaped member mounted therein providing a shelfand a back wall and arranged to receive heat exchange fluid therethrough.

A still further object of the invention is to provide an evaporator unitfor mechanical refrigerators wherein contiguous metal sheets form theback wall of the unit and are embossed to define refrigerant "dryingducts receiving spent refrigerant from the unit. v A

Other and further objects of the invention will be apparent to thoseskilled in the art from the following detailed description of theannexed sheets of drawings which, by way of a preferred exampleillustrate one embodiment of the invention.

On the drawings:

Figure 1 is a side elevational view of an evaporator unit according tothis invention.

Figure 2 is a front end elevational view of the unit of Fig. 1.

Figure 3 is a top .plan view of the unit of Figs. 1 and 2.

Figure 4 is an enlarged fragmentary horizontal cross sectional viewtaken along theline IV-IV 'of Fig. 2.

As shown on the drawings:

In Figs. 1 to 4 the reference numeral I0 designates generally a sheetmetal evaporator unit according to this invention. The unit I iscomposed of embossed brazed or welded togethercontiguous metal sheets orplates including an inner sheet I I and an outer sheet I2. The sheets IIand I2, after being secured together, are bent so as to provide a bottomwall portion Illa, spaced opposed vertical side wall portions, IIl'b,Illb, and

inturned horizontal top fianges IIlc. Illc at the upper ends of the sidewall portions Ib, Ib. These flanges |0c, Ic have apertures I3` thereinas best shown in Fig. 3 to receive studs or mounting bolts forsuspending the unit i0 in the top portion of a refrigerator cabinet (notshown).

A shelf and back wall unit I4, composed of contiguous Welded togetherembossed metal sheets or lplates I5 and ||i is mounted in the chamber Cdefined by the unit I0. The member I4 is bent into the shape of an L andhas a horizontal leg I4a providing a shelf in the unit I0 together witha vertical leg |4b providingia back wall for the unit I0. f

Angle brackets I1 are provided to mount the member I4 in the unit I0. Asbest shown in Fig. 2 these brackets have vertical legs Ila attached tothe side walls I 0c of the unit III near the tops of the side walls,together with horizontal legs Hb extending into the chamber C in spacedparallel relation under the anges Ille. Rivets, such as I8, are providedto connect the legs Ila. to the side walls IIIb as best shown in Fig. 1.The horizontal leg |4a of the member I4 rests on the horizontal legs |1bof the brackets I1 and rivets, such as I9, are provided to connect themember I4 to the bracket. As shown in Fig. l brackets I1 are provided atthe front and rear ends of the side wall IIlb.

As best shown in Figs. 1 and 2, the outer sheet or plate I2 of the unitII) is embossed to provide an inlet manifold duct 20 along the bottomIlla midway between the side walls IIlb. This duct 20 extendslongitudinally from the rear portion to the front portion of the unitand has a closed end 20a, in spaced relation from the front edge of theunit, together with an enlarged end 2U!) in spaced relation from therear edge of the unit.

Feeder ducts 2| are also embossed in the outer plate or sheet I2 andextend laterally outward from the inlet manifold duct 20. These ducts 2|are in spaced parallel relation and traverse the entire bottom I0a ofthe unit and extend around into the side walls of the unit to levelsjust above the rounded corners between the side walls and bottom.'I'hese feed ducts 2| serve to distribute refrigerant from the inletmanifold 20 to the side wall portions |0b of the unit IIJ at equallyspaced intervals along ther lengthv of the side walls.

Embossments are provided in the outer sheet I2 near the tops of the legsor side walls IIlb to define in each leg or side wall a pair ofsuperimposed longitudinal outlet manifold ducts, including a bottom duct22 and a top duct 22a.

`The ducts 22 and 22a are connected at the front end of the side wall bya duct 22h.

The outer sheet I2 is further embossed to provide spaced upstandingcollecting ducts 23 depending from the outlet manifold ducts 22 in theupper portions of the side walls |0b of the unit. These collecting ducts23 as best shown in Fig. 1 are aligned with upper ends of the feederducts 2|.

The outer sheet I2 is still further embossed in the side Wall portionsIIlb thereof to define criss-crossed diagonal or sloping heat exchangerducts 24 connecting the upper ends of the feeder ducts 2| with the lowerends of the collecting ducts 23. These sloping ducts 24 are so arrangedthat two ducts 24 diverge from each duct 2| and 23 except at the endducts 2| and 23. The ducts 24 intersect each other at points 24a todefine a grid-like design in the side walls I0b with diamond-shaped flatsheet portions D bounded by duct-defining beads or embossments. Thesloping ducts 24 extending from the end ducts 2| and 23 slopediagonallyinward and converge with an oppositely sloping duct at their other end.Outwardly sloping ducts 24 which would normally diverge beyond matingrelation with the distributing or collecting ducts 2| or 23, mate witheach other at points 24h at the front and rear portions of the sidewalls 0b.

Refrigerant from the feeder ducts 2| is distributed throughoutsubstantially the entire faces of the side walls |0b of the unit by thegrid-like arrangement of sloping ducts 24 and at the same time the ducts24 only have semi-cylindrical cross sectional areas as best shown inFig. 4. The labyrinth passages provided by the ducts afford amplecapacity for relatively large volumes of refrigerant without collectingthe refrigerant in any chamber of large cross sectional area. As aresult the refrigerant is maintained in excellent heat exchange relationwith the sheets and I2.

Since the ducts 20 to 24 are all defined by embossments in the outersheet I2. the chamber C enclosed by the unit I0 is free from inwardlyprotruding embossed portions and will have increased storage space.

The shelf portion I4a of the member I4 has the bottom sheet I6 thereofembossed, as shown in Fig. 3, to provide a serpentine duct 25 whichextends from an upstanding inlet collar 26 formed on the upper sheet I4aat the rear end of the shelf forwardly vand rearwardly in a series ofcoil-like turns to an upstanding outlet flange 21 transversely alignedwith the collar 26. An inlet tube or fitting 28 is brazed in the flange28 to supply refrigerant to the duct 25. An outlet tube or fitting 29 isbrazed or otherwise secured in the flange 21 and is connected by meansof a tube 30 with the enlarged portion 20h of the inlet manifold duct20. Refrigerant thus is introduced through the shelf portion Ida to therear end of the'mani- These upstanding legs are at the rear end of the`shelf. 1

The back wall-defining portion or vertical leg AMb ofthe member I4 hasthe inner sheet I6 thereof embossed to define spaced parallel verticalducts 3l as best shown in Fig. 2. The top ends of the two innermostducts 3| are connected by a horizontal duct 32 embossed in the outer orback sheet l of the leg Mb. The duct 32 has an outwardly extendingcylindrical flange portion 33 embossed thereon and receiving an outlettube or fitting 34. This ange 33 is midway between the ends of the duct32.

The lower ends of adjacent ducts 3l are connected by a pair ofsuperimposed parallel ducts 35 embossed in the outer or rear sheet l5 ofthe member I4 near the bottom of the back wall Mb. The lower ducts 35 ofeach pair provide collecting sumps for unspent refrigerant while theflow of spent refrigerant is unimpeded through the upper ducts 35. Theunspent refrigerant in the lower ducts 35 soon becomes exhausted sinceit is in excellent heat transfer relation with the refrigerated spacesurrounding the unit and, when exhausted, it is drawn upwardly into'theduct 32 through the innermost ducts 3|.

'I'he top ends of the outer ducts 3l have rearwardly extendingcylindrical flanges 36 receiving tubes or fittings 3l connected at theirupper ends to cylindrical flanges 38 extending inwardly fromthe rearends of the outlet manifold ducts 22a.

Refrigerant is thus collected from the outlet ducts 22a by the tubes 31and flows in a serpentine path through the ducts 3l and 35 to the centerof the back wall Mb. These ducts 3l and 35 provide a dryingvtube andsumps for the refri-gerant to afford additional heat-absorbing surfacesthrough which the spent refrigerant from the outlet manifold 22must'pass before it reaches theexhaust'tube 34.

From the above description it should be understood that the heatexchanger or evaporator unit of this invention is free from enlargedheader chambers and has a drying circuit made as a part of the back wallof the unit in a member supported by the unit and also providing a shelfin the unit. The criss-crossed diagonal or sloping distributing ductsare formed by shallow embossments on the outer surfaces only of the unitbut due to their intersecting grid-defining arrangement, have largecapacity without at .any time collecting the refrigerant in a chamber oflarge cross-sectional area. 'I'his arrangement maintains the refrigerantin relatively small diameter flowing columns to have increased heatexchange relationship with the walls of the unit. The elimination ofheaders which heretofore projected into the storage space C of U-shapedrefrigerator units creates increased storage space for ice trays and thelike in the units of this invention. The superimposed outlet manifoldducts 22 and 22a are connected at their front ends and the top duct isexhausted out of its rear end so that refrigerant being removed from theunit must traverse the entire length of the unit. This arrangementprevents any short circuiting possibilities which might produce warm ordefrost areas on the unit especially at the upper front corners of theunit.

The use of shallow embossments only on the outer faces of the unitaccommodates mounting the unit close to the walls of a refrigeratorcabinet, thereby conserving cabinet space. The units of this inventionare especially satisfactory for mounting in an upper corner of thestorage space of a refrigerator cabinet.

It will, of course, be understood that various details of constructionmay be varied through aV wide range without departing from theprinciples of this invention and it is, therefore,not the pur pose tolimit the patent granted hereon otherwise than necessitated by theiscopeof the appended claims.

I claim as my invention:

1. A heat exchanger comprising contiguous secured together U-shapedmetal sheets forming the bottom and side walls of a chamber, at leastone of said sheets being embossed to dene a. longitudinal inlet manifoldduct along the bottom, feeding ducts extending laterally from themanifold duct and thence upwardly into the lower ends of the side walls,oppositely sloping ducts extending upwardlyv from the upper ends of thefeeding ducts and the oppositely sloping ducts extending from one ofsaid feeding ducts each intersecting with a plurality of the othersloping ducts to form a grid-like pattern on the side walls, upstandingcollecting ducts at the upper ends of the oppositely sloping ducts, andlongitudinal outlet ducts. at the upper ends ofthe collecting ducts,contiguous secured to gether L-shaped metal sheets mounted in saidchamber to provide a shelf and a back wall and having a shelf duct and aback wall duct, means for vintroducing fluid into the shelf duct, a tubeconnecting said shelf duct and the inlet manii fold duct, tubesconnecting the longitudinal outlet ducts with the back wall duct, and anoutlet tube for exhausting said back wall duct.

2. A heat exchanger comprising inner and outer contiguous metal sheetssecured together along contacting faces thereof and bent into U-shape toprovide the bottom and side walls of an enclosed space, said outer sheetbeing embossed to define a longitudinally extending inlet duct along thebottom, a plurality of spaced feeding ducts extending `laterally outwardfrom the inlet duct along the bottom and thence upwardly into the lowerportions of the side walls, longitudinally extending outlet ducts in the`upper ends of the side walls having a plurality of depending collectingducts and criss cross oppositely inclined diagonal ducts in a grid-likearrangement in the side walls communicating at their lower ends'with theupper ends of the feeding ducts and at their upper ends with thedepending collecting ducts of said outlet ducts whereby heat exchangefluid introduced into. the inlet manifoldxwill be distributed in aplurality of -individual ducts to the lower ends of the side walls ofthe heat exchanger and will thence flow in a multitude of criss crossedpaths to the upper ends of the side walls for removal through saidoutlet ducts.

3. An evaporator unit for mechanical refrigerators or the like whichcomprises contiguous secured together embossed metal sheets bent todefine a sharp freezing chamber and embossed to denne a single inletmanifold duct, a plurality of feeding ducts extending in spaced relationfrom opposite sides of the inlet manifold duct and a plurality ofoppositely inclined distributing ducts communicating with the feedingducts and arranged in a grid-like pattern to distribute refrigerantalong a labyrinth arrangement of paths each of relatively small crosssectional area to enhance heat transfer from the refrigerant to thewalls of the unit, and an outlet manifold duct communicating with theupper ends of the distributing ducts.

4. An evaporator unit comprising contiguous secured-together embossedmetal sheets bent into U-shape to provide bottom and side walls fordefining a sharp freezing chamber, at least one of said sheets beingembossed to define an inlet manifold duct extending longitudinally alongthe central portion of said bottom from the front to the rear of theunit, a plurality of laterally extending feeding ducts in spacedvrelation along the bottom of the unit and continuing around the bottomcorners of the unit into the side walls of the unit, criss-crossedoppositely sloping sets of refrigerant-spreading ducts in said sidewalls diverging from the upper` ends of the feeding ducts-spacedparallel upstanding collecting ducts at the converging upper ends of thediagonal ducts to receive refrigerant therefrom, lower longitudinallyextending outlet manifold ducts receiving the upper ends of thecollecting ducts and upper longitudinally extending manifold ductsspaced above said lower manifold ducts and connected therewith at thefront ends of the side walls, an L-shaped member composed of embossedcontiguous secured-together metal sheets in said sharp freezing chambercarried by the side walls of said unit to provide a shelf and a backwall for the unit, said shelf portion of the member having a duct forrefrigerating the shelf, a refrigerant inlet connected to one end ofsaid shelf refrigerating duct together with a refrigerant outlet at theend of the duct remote from the inlet end thereof, a tube connectingsaid outlet with said inlet manifold of the unit, said back Wall portionof the member having refrigerant ducts therein with an outlet. at thecentral portion thereof and with inlets at the outer end portionsthereof, said back wall refrigerant ducts having bottom sump ductsbetween the inlets and outlet, and tubes connecting the rear ends of theupper outlet manifold ducts of the unit with the upper outer endportions of the refrigerant ducts in said back wall portion.

5. A sheet metal evaporator for mechanical refrigerators comprising aU-shaped unit having duct containing side walls and a duct containingbottom, an L-shaped duct defining member mounted in said U-shaped unitto define a horizontal shelf with a first set of ducts and a verticalback wall with a second set of ducts, means for introducing refrigerantinto the first set of ducts, a tube connecting said first set of ductswith the ducts in said bottom, and tubes connecting the ducts in saidside walls with the second set of ducts to dry refrigerant exhaustedfrom the unit in said vertical back wall before the refrigerant leavesthe evaporator.

6. An evaporator unit comprising a U-shaped member defining a sharpfreezing space and having refrigerant-distributing ducts in the walls 8thereof with outlets -at the upper ends ofthe side legs, an L-shapedmember in said U-shaped unit having a horizontal leg providing a shelfin the sharp freezing space enclosed by the unit and a,

vertical leg depending from said horizontal leg forming a back wall forthe unit. said vertical leg having ducts therein with upstandingportions connected at their lower ends by spaced superimposedhorizontalducts, and transfer tubes connecting the outlets of the ductsin the unit with the ducts in the back wall of the L-shaped member.

7. An evaporator unit comprising contiguous secured-,together embossedmetal sheets bent into U-shape to provide a bottom wall and side wallsfor deflning a sharp freezing chamber, at least one of said sheets beingembossed to define an inlet manifold duct extending longitudinally alongthe central portion of said bottom from the front to the rear of theunit, refrigerant-spreading ducts in at least one side wall, meansproviding communication between said refrigerant-spreading ducts andsaid inlet manifold duct, a longitudinally extending outlet manifoldduct in at least one side wall, means providing communication betweensaid refrigerant-spreading ducts and said outlet manifold duct, anL-shaped member composed of embossed contiguous secured-together metalsheets in said sharp freezing chamber carried by the side walls of saidunit to provide a shelf and a back wall for the unit, said shelf portionof the member having a duct for refrigerating the shelf, a refrigerantinlet at one end of said shelf-refrigerating duct, a refrigerant outletat the other end of said duct remote from the inlet end thereof, meansconnecting said refrigerant outlet with said inletv manifold duct of theunit, said back wall portion of the member having refrigerant ductstherein with at least one inlet and outlet, said back wall refrigerantducts having bottom sump ducts between the inlet and outlet, and meansconnecting the rear end of the outlet manifold duct of the unit with theinlet of said refrigerant ducts in said back wall portion, wherebyrefrigerant circulates through said shelf-refrigerating duct, throughsaid inlet manifold duct, through said refrigerant-spreading ducts insaid side wall, through said outlet manifold duct, and into therefrigerant ducts in said back wall portions, through the bottom sumpducts, and through the outlet of said refrigerant ducts in said backwall portion.

8. An evaporator unit comprising contiguous secured-together embossedmetal sheets bent into U-shape and having an embossed longitudinallyextending duct in at least one of the upper ends of the side legs, aback wall on said unit composed of embossed secured-together metalsheets having a first duct therein with an upper inlet end adjacent saidone side leg, a second duct having an upper outlet end remote from saidone side leg, superimposed parallel ducts at the bottomof said backwall, one end of each parallel duct being connected with said firstduct, the other end of each parallel duct being connected with saidsecond duct, an outlet tube communicating with the outlet end of saidsecond duct in the back wall, and a transfer tube connecting the rearendof the upper longitudinally extending duct in said one side leg of theunit with the inlet end of the first duct in said back wall.

BERNARD C. JOHNSON.

(References on following page) REFERENCES CITED The following referencesare of record in the le of this patent:

UNITED STATES PATENTS Number Number Name Date Newman June 13, 1939Steenstrup Maan-11, 1941 Raskin June 3,1941 Beane May 23, 1944 JohnsonOct. 9, 1945 FOREIGN PATENTS Country Date Great Britain June 21, 1906

